22. Pulse-code modulation (PCM)
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals.
It is the standard form of digital audio in computers, Compact Discs, digital telephony and other digital audio applications.
In a PCM stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps.

26. 12/3/201812/3/201812/3/201812/3/201812/3/201812/3/201812/3/201812/3/201812/3/2018
Channel Coding
The process of digitally processed and encoded of the output of the transmitter encoder through the communication channel. This is to control the errors during the transmission process.

32. In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.